Understanding Myopathies

Myopathies are neuromuscular diseases which cause muscle fibres not to function, so resulting in muscular weakness. There are many types of myopathy - this website deals primarily with centronuclear and myotubular myopathy, however, if you have stumbled across these pages wanting to read about another type of myopathy, the information below may be of assistance.

Congenital Myopathies

Centronuclear and myotubular myopathy are congenital myopathies. The term congenital myopathy refers to a group of muscle disorders that appear at birth or in infancy. At birth a child with a congenital myopathy will most probably be 'floppy' (this is known as hypotonia), have difficulty breathing and feeding and will be slower than other babies in meeting developmental milestones such as turning over, sitting up, walking and maybe even talking.

The National Institute of Neurological Disorders and Stroke reports there are seven types of congenital myopathy including centronuclear and myotubular myopathy.

  • Central Core Myopathy

Severity of problems and the degree to which the condition worsens over time varies among those affected. Usually though there is mild floppiness in infancy, delayed milestones and some weakness of limbs which does not worsen much over time. Children may have life-threatening reactions to general anesthesia. Treatment with the drug salbutamol has been shown to reduce weakness significantly, although it does not cure the disorder.

Further information about central core myopathy is available on the Muscular Dystrophy Campaign website.


  • Congenital fiber-type disproportion myopathy

Particularly rare myopathy characterised by floppiness, limb and facial weakness, and breathing problems.


  • Myosin storage myopathy (Hyaline body myopathy)

Is thought to have several different causes, as a a result of which, symptoms can vary. The condition is characterised by the specific appearance under the microscope of a sample of muscle tissue.


  • Multi-minicore disease

A condition with several different subtypes. Most people with the condition have severe weakness of the limbs and scoliosis. Breathing difficulties may also occur and some children have weak eye movements.

Further information about Multi-minicore disease is available on the Muscular Dystrophy Campaign website.


  • Nemaline (Rod) Myopathy

Most common of the congenital myopathies. Infants usually have problems with breathing and feeding. Some skeletal problems may arise later such as scoliosis (curvature of the spine). In general, the weakness does not worsen during life.

Further information about Nemaline (rod) myopathy is available on the Muscular Dystrophy Campaign website and from the Nemaline Myopathy support group.

 

Other Myopathies

Mitochondrial Myopathies

Mitochondrial disease occurs when the mitochondria of a cell fails to produce enough energy for a cell or organ to function. Mito dysfunction is known to occur in many myopathies, even if it is secondary to the primary myopathy.

There are many forms of mitochondrial disease and the disease can be inherited in a number of different ways. Diseases of the mitochondria may cause damage to the brain, heart, liver, skeletal muscles, kidney and the endocrine and respiratory systems.

Further information about Mitchchondrial diseas can be obtained from The United Mitochondrial Disease Foundation and Mito Action websites.

 

Lipid Storage Myopathies and Glycogen Storage Myopathies

Also know as metabollic disorders, these myopathies are:

  • Carnitine deficiency
  • Carnitine palmityl transferase deficiency
  • Myoadenylate deaminase deficiency
  • Pompe's disease
  • Cori Forbes' disease
  • McArdle's disease

Further information abut Glycogen Storge Myopathy is available at The Association of Glycogen Storage Disease UK website.

 

Myofibrillar myopathies

Information about Myofibrillar myopathies is available from Gene Reviews and Orphanet.

 

Myositis

Also known as inflammatory myopathies these myopathies are:

Information about Myositis is available from the Myositis Support Group. Information about Polymyositis, Dermatomyositis and Sarcoid mupathy is available from the Muscular Dystrophy Campaign website.


Further Information

Information about all these conditions can be found in the report 'Muscle Disease: The Impact' (436 kb) from the Muscular Dystrophy Campaign.

Information about congenital myopathies can be found at e-medicine and further information about myopathies can be found at Patient UK.